properties of hydrocarbons fuels

• as length of carbon chain increases, fuels become darker in colour, more viscous, less flammable and harder to ignite
• viscous

  fluid which does not flow easily
• fuels with short carbon chains tend to burn more cleanly and produce less soot than those with long carbon chains
• colour

  darkens as number of carbon atom increases, eg. petrol no colour, fuel dark orange, bitumen black
• viscosity

  increases as number of carbon atoms increases, eg. petrol runny and easy flow, fuel thick and viscous
• ease of ignition

  decreases as number of carbon atoms increases, petrol ignites easy, fuel oil difficult, bitumen won't ignite
• sootiness of flame

  increases as number of carbon atoms increases, eg. petroleum gases burn easily with blue flame, kerosene produces a lot of smoke and soot when burnt